Zirconium Hafnium Oxide Gate Stack Leakage Reduction
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Solution Overview
Problem
High-k thin layers in semiconductor devices, such as zirconium oxide, often suffer from poor surface morphology leading to current leakage due to electric field concentration, and hafnium oxide's low dielectric constant makes it unsuitable for recent semiconductor devices.
Innovation Solution
A method of forming a zirconium hafnium oxide thin layer using a mixture of tetrakis(ethylmethylamino)zirconium (TEMAZ) and tetrakis(ethylmethylamino)hafnium (TEMAH) precursors with an oxidizing agent on a semiconductor substrate, which forms a gate insulation layer or dielectric layer with improved dielectric constant and surface morphology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If zirconium oxide is used to increase dielectric constant, then dielectric constant is improved, but surface morphology deteriorates leading to current leakage
Solution Approach 1:
The patent applies composite materials by combining zirconium oxide and hafnium oxide in a layered structure. The zirconium oxide layer provides high dielectric constant (k≈55), while the hafnium oxide layer provides good surface morphology and fills in surface irregularities. This composite approach resolves the contradiction by allowing each material to contribute its advantageous property to the overall thin layer structure.
Solution Approach 2:
The patent implements local quality by creating distinct regions with different material compositions within the thin layer. The zirconium oxide region provides high dielectric constant where needed, while the hafnium oxide region provides surface smoothing and field distribution. This spatial differentiation allows each material to perform its specialized function locally, resolving the contradiction between dielectric constant and surface morphology.
2Reliability
If hafnium oxide is used to improve surface morphology, then surface morphology is improved, but dielectric constant deteriorates due to low k value
Solution Approach 1:
The patent uses composite materials to combine the surface morphology benefits of hafnium oxide with the high dielectric constant of zirconium oxide. The layered structure allows hafnium oxide to provide surface smoothing while zirconium oxide contributes the necessary high-k property, thus resolving the contradiction between these two opposing characteristics.
Solution Approach 2:
The patent merges two different oxide materials into a single functional thin layer structure. By combining hafnium oxide and zirconium oxide in specific configurations, the invention achieves both good surface morphology and high dielectric constant, resolving the contradiction by integrating the strengths of both materials into one system.
3Loss of energy
If thin layer thickness is reduced to minimize current leakage, then current leakage is reduced, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent applies composite materials in a layered configuration where each layer can be independently formed and controlled. This allows the total thickness to be optimized for minimal current leakage while each individual layer's thickness can be precisely controlled during separate deposition processes, resolving the contradiction between thinness and manufacturability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The zirconium hafnium oxide layers reduce current leakage and enhance the dielectric constant, providing better electrical characteristics for semiconductor devices by offering a higher dielectric constant and improved surface morphology compared to pure hafnium or zirconium oxide layers.
Implementation Method 1
supplying a mixture of TEMAZ and TEMAH and an oxidizing agent to the substrate
Implementation Method 2
a method of forming a zirconium hafnium oxide layer by a chemical vapor deposition (CVD) process
Data Source
AI summary
Methods of forming a zirconium hafnium oxide thin layer on a semiconductor substrate by supplying tetrakis(ethylmethylamino)zirconium ([Zr{N(C2H5)(CH3)}4], TEMAZ) and tetrakis(ethylmethylamino)hafnium ([Hf{N(C2H5)(CH3)}4], TEMAH) to a substrate are provided. The TEMAZ and the TEMAH may be reacted with an oxidizing agent. The thin layer including zirconium hafnium oxide may be used for a gate insulation layer in a gate structure, a dielectric layer in a capacitor, or a dielectric layer in a flash memory device.